SQL correct way of joining if the other parameter is null

Question

I have this code and its temporary tables so you can run it.

create table #student
(
    id int identity(1,1),
    firstname varchar(50),
    lastname varchar(50         


        

Answer 1

My take on it - similar to Patrick's answer with a cross join.

Full sample available at sqlfiddle

select
  Q.Quiz_Name Quiz
 ,S.LastName Last
 ,S.FirstName First
 ,QD.Quiz_ID
 ,QD.Student_ID
from 
/* Get a full list of ALL Test/Student combinations */
           quiz Q 
CROSS JOIN student S 
/* Join the taken tests to the combinations */
 LEFT JOIN quiz_details QD on Q.id = QD.quiz_id
                          and S.id = QD.student_id
/* Only select where no Quiz_ID exists */
WHERE QD.Quiz_ID IS NULL
ORDER BY Q.Quiz_Name, S.Lastname, S.FirstName;